This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Carbonyl reductase (CR) catalyzes the NADPH-dependent reduction of a wide range of carbonyls. CR has been connected to several important processes including but not limited to quinone detoxification, neuroprotection, prostaglandin metabolism, and, of clinical interest, anthracycline metabolism. CR reduction of anthracyclines significantly impacts their use in the treatment of cancer as it has been linked to both drug resistance and cardiotoxicity mechanisms. Therefore, inhibition of CR in conjunction with anthracycline therapy offers the potential both to increase the effectiveness of the drugs and to decrease the risk of the associated cardiotoxicity. The major emphasis of this work is to better understand how CR recognizes the molecules to which it binds, be they substrates or inhibitors. Equipped with this information, drugs may be designed to control CR with the intention of reducing the risk of cardiotoxicity during anthracycline cancer treatment. Also, as the role of CR in other pathways is better understood, such drugs may be used to treat other diseases as well.